Finding the Fourth Proportional to 2,113.60, 3,168.78 and 816.16

Step by Step Solution

1. Step 1: Write the proportion equation
   2,113.60 : 3,168.78 = 816.16 : x
2. Step 2: Convert to fraction form
   2,113.60/3,168.78 = 816.16/x
3. Step 3: Cross multiply
   2,113.60x = 3,168.78 × 816.16
4. Step 4: Simplify right side
   2,113.60x = 2,586,231.48
5. Step 5: Solve for x
   x = 2,586,231.48/2,113.60
6. Step 6: Final answer
   x = 1,223.61